During an appearance before lawmakers on the Senate’s Finance Committee, Treasury Secretary Janet Yellen was repeatedly pressed in often heated terms by Republicans about the lack of a Social Security plan in President Biden’s recent budget proposal.

“Anyone who knows how things get done around here knows it takes presidential leadership to lead major reforms," said Sen. Chuck Grassley (R-IA) on Thursday morning soon after the hearing got underway.

That exchange was soon followed by an intense back and forth with Sen. Bill Cassidy (R-LA) who pressed the Secretary in often personal terms on the president's approach to the issue and claims from Democrats that Republicans seek to cut the program.

“That’s a lie” Cassidy said after Yellen said that Biden stood ready to work with Congress on the issue.

"Why doesn't the president care?" he also asked, noting that he is involved in bipartisan talks on the issue, but hasn’t been able to get an Oval Office meeting to discuss further.

In response, Secretary Yellen offered a defense of her and Biden’s motives, but provided few new details beyond saying that Social Security is a priority for the president and reiterating that the Biden administration would agree to no benefit cuts.

"It's a discussion we need to have," she said.

After the exchange with Cassidy, Finance Committee Chair Ron Wyden (D-OR) jumped in to admionish his colleague and say Cassidy had gone “over the line.” Cassidy responded that he didn’t mean to say Secretary Yellen was lying and that she was only passing along what President Biden has told her.

"Welcome to the Senate Finance Committee Secretary Yellen, we are normally a pretty jovial group," the next questioner, Sen. Tom Carper (D-DE) quipped before moving on to other topics.

Thursday's back and forth comes after another tense exchange on the issue between Sen. Mitt Romney (R-UT) and Shalanda Young, Biden's director of the White House Office of Management and Budget, on Wednesday.